Apparatus for agglomerating dusts and the like

ABSTRACT

Apparatus for agglomerating fine particles including a rotatable mixer, generally resembling a rotary drum dryer, having optionally a conveyor, such as a spiral vane, as an aid in moving particulate base material therethrough, an applicator, such as a manifold with spray nozzles for applying a liquid or another solid particulate material to the base material and thereby effecting coating and agglomeration of the base material, and lifter elements mounted within the mixer and rotatable therewith adapted to move through the normally relatively dormant central region of the mass of base material and thereby cause the base material in this region to become mixed with the base material in the normally actively moving inner and outer regions of said mass.

United States Patent Inventor Appl. No.

Filed Patented Assignee APPARATUS FOR AGGLOMERATING DUSTS AND THE LIKE10 Claims, 8 Drawing Figs.

[1.8. CI 259/3 Int. Cl 1301f 9/06 Field of Search 259/3, 14,

Primary Examiner-Robert W. Jenkins Attorneys-Daniel C. Block and EdwinH. Baker ABSTRACT: Apparatus for agglomerating fine particles includinga rotatable mixer, generally resembling a rotary drum dryer, havingoptionally a conveyor, such as a spiral vane, as an aid in movingparticulate base material therethrough, an applicator, such as amanifold with spray nozzles for applying a liquid or another solidparticulate material to the base material and thereby effecting coatingand agglomeration of the base material, and lifter elements mountedwithin the mixer and rotatable therewith adapted to move through thenormally relatively dormant central region of the mass of base materialand thereby cause the base material in this region to become mixed withthe base material in the normally actively moving inner and outerregions of said mass.

Patented May 25, 1971 3,580,545

3 Sheets-Sheet l INVENTOR. EDWARD D. O BRIEN BY WNW ATTORNFY PatentedMay 25, 1971 3 Sheets-Sheet 2 INVENTOR. EDWARD D. O'BRIEN BY ug-AwATTORNEY Patented May 25, 1971 3,580,545

3 Sheets-Shoat 5 INVENTOR EDWARD D. O'BRIEN BY EJANMJ ATTORNEY APPARATUSFOR AGGLOMERATING DUSTS AND THE LIKE This application is acontinuation-in-part of copending application Ser. No. 652,992, filedJuly 12, 1967, now abandoned.

In a drum having an input end adapted to receive fine particles to beagglomerated by application of an agglomerating agent, an output end todischarge the particle agglomerates, optionally an internal peripheralspiral vane, or other suitable conveyor element, to convey the materialthrough the drum, an applicator to apply the agglomerating agent to theparticles, as by either spraying the same into one or more fallingcurtains of particles or by injecting the same into the main mass ofparticles at the bottom of the drum, the improvement comprising theprovision of a plurality of elongated rods, or the equivalent thereof,disposed substantially parallel to each other and to the longitudinalaxis of the drum and radially-inwardly of the conveyor element, or, ifno conveyor element is present, then radially inwardly of the insidewall of said drum, and adapted to be laterally moved through thenormally rela tively dormant region of the main mass of particles at thebottom of the drum to disturb and move the particles within said dormantregion and cause them to be mixed with actively moving particles locatedoutside of said dormant region and to lift particles out of said mainmass and cause them to thereafter cascade downwardly onto said main massin the form of one or more curtains of falling material into which theagglomerating agent may be sprayed without the deposit of anyagglomerating agent on said rods.

The subject apparatus also embodies means for screening out finesadjacent the output end of the drum and for retuming them lengthwise ofthe drum into the input end of the drum.

With reference to the general purpose, use and function of the subjectapparatus, and to the types, identities, sizes and other characteristicsof the particulate materials and agglomerating agents which the subjectapparatus may readily handle, such is known or easily determined bythose skilled in the art.

THE DRAWINGS FIG. 1 is a view in side elevation, partly broken away andpartly in section, of one form of apparatus embodying the invention;

FIG. 2 is an endwise view in perspective, taken from the output end ofthe drum portion of the apparatus of FIG. 1;

FIG. 3 is a view in side elevation, partly broken away and partly insection of another form of apparatus embodying the invention;

FIG. 4 is an endwise view in perspective, taken from the output end ofthe drum portion of the apparatus of FIG. 2;

FIG. 5 is an enlarged partial view in transverse section of the drumportion of the apparatus of FIG. 2 illustrating the mode of operation ofa preferred form of the improvement embodying the subject invention;

FIG. 6 is a view in transverse section of the drum portion of a modifiedform of the apparatus of the invention;

FIG. 7 is a view in transverse section of another modified form of theapparatus of the invention; and

FIG. 8 is a view in perspective, an end of the drum being shown insection, of another modified form of the apparatus of the invention.

Referring to the drawings, with particular initial reference to FIG. 1or FIG. 3, the apparatus may generally comprise a frame 10 having anangularly adjustable bed 12, two-way acting power means I4 toselectively position bed 12 at any desired angle relative to thehorizontal, a cylindrical drum 16, means 18 and 20 to rotatably supportthe drum on bed 12, and variable speed drive means 22, 24, and 26 torotate the drum.

In the embodiment of the apparatus of this invention shown in FIGS. 1and 2, drum 16 comprises: an outer cylindrical shell or wall 26; anannular end plate 32 defining an input opening 34 for the baseparticulate material 36; an annular end plate 38 defining an outputopening 40 disposed in'feed relation to a receiver 42 for theagglomerate material 44; an agglomerating agent feed line 56 providedwith a plurality of spaced spray nozzles 58 (FIG. 2); and a cylindricalbundle of parallel spaced cylindrical rods 60 carried by end rings 62positioned against drum end plates 32 and 38.

It will be appreciated that, except for feed line 56, all of theabove-described components of drum l6 rotate together as an integratedconstruction.

In another embodiment of the apparatus of this invention shown in FIGS.3 and 4, drum 16 comprises: an outer cylindrical shell or wall 28; aninner cylindrical shell or wall 30; an annular end plate 32 defining aninput opening 34 for the base particulate material 36; an annular endplate 38 defining an output opening 40 disposed in feed relation to areceiver 42 for the agglomerate material 44; a spiral conveyor vane 46to help move the material 36 through the drum; a cylindrical screen 48of a mesh size to pass fines 49 (FIG. 4) to the annular chamber 50between shells 28 and 30; a spiral conveyor vane 52 in chamber 50 toreturn the fines to the input end of the drum; ports 54 at the input endof inner shell 30 to permit the fines to refeed into the inner shell forrepassage therethrough; an agglomerating agent feed line 56 providedwith a plurality of spaced spray nozzles 58 (FIG. 2); and a cylindricalbundle of parallel spaced cylindrical rods 60 carried by end rings 62positioned against drum end plates 32 and 38.

The embodiment of the apparatus of this invention shown in FIGS. 3 and 4shows a conveyor means (spiral conveyor vane 46) disposed within thedrum between the inner surface of shell or wall 30 and the cylindricalbundle of parallel spaced cylindrical rods 60. Although it is preferredto so dispose a conveyor means in drum 16 to help move material 36through the drum, a conveyor means is not necessary to so move material36.

Again, it will be appreciated that, except for feed line 56, all of theabove-described components of drum 16 rotate together as an integratedconstruction.

With reference to FIGS. 2 and 4, the drum is shown as rotating in acounterclockwise direction, the material 36 therefore tending to assumean overall sloped configuration, being piled up toward the right inFIGS. 2 and 4. As is shown in FIG. 2 the lower strata of material 36moves in a counterclockwise direction under the influences of rods 60and a drag effect imparted by shell 30. In the embodiment shown in FIG.4, the lower strata of material 36 moves in a counterclockwise directionunder the influence of vane 46, rods 60 and a drag effect imparted byshell 30. The upper strata of material 36 moves in a clockwise directionunder the influence of gravity acting on the sloping pile. Between theseoppositely moving upper and lower strata the central strata or region ofthe material 36 tends to be stationary or dormant between thecountermoving upper and lower strata.

One of the functions served by the rods 60 is to move through thedormant region and impart movement to the material within this region,thereby causing this normally dormant material to be moved upwardly andto thereafter become mixed with the normally moving upper and lowerstrata material. Thus, the rods 60 act as a mixing and homogenizingmeans. Because of this function of the rods 60, none of the particulatebase of feed material may remain covered over and dormant, andtherefore, none of the base material passes through the drum withoutadequate exposure to the agglomerating agent, whether the latter bespray-applied, as in FIGS. 2 and 4-7, or whether it beinjection-applied, as in FIG. 8, hereinafter described.

Further important functions served by the rods 60 are as follows: theylift or convey the base material upwardly along the wall of (FIGS. drum(FIGS. 2, 4 and 5) to a greater extent than (FIGS. would occur in theirabsence; and they permit the material to cascade over and around them,i.e. through the spaces between adjacent rods FIGS. 2, 4 and 5), therebycausing the formation of a plurality of vertically disposed andhorizontally spaced curtains, into which the agglomerating agent issprayed FIGS. 2, and d-7 As indicated in FIGS. 2, 4 and 5, the sprayheads or nozzles 58, emit the agglomerating agent, normally andtypically a sticky liquid, in a vertically narrow and horizontally broadspray pattern. There are a plurality of curtains of falling materialbetween the nozzles and the particular rod or rods disposed in the pathof movement of the agglomerating agent spray. An important consequenceof this is neither the rods, nor any of the other components of thedrum, become wetted or contacted by the agglomerating agent. Thus, nogumming up of the equipment occurs, and need for equipment stoppages forclean-outs is eliminated. It is of importance, relative to theprotection of the rods against wetting by the agglomerating agent, thatthe agglomerating agent liquid not be atomized by the spray head system.Hence, conventional spray heads are selected to provide a flat,fanshaped droplet spray pattern.

A further important consequence of spraying the agglomerating agent intoone or more active, moving curtains of particulate material is that theend product agglomerate is obtained with a minimum of lumps.

Typical dimensional, operational and other data concerning the apparatusare as follows: a 60 inch diameter drum is a practical size; the rods 60may be formed of metal and be relatively stiff or they can be resilient,e.g. formed of a flexible rubber; for a 60 inch diameter drum and sprayapplication of agglomerating agent, the rods 60 can, for example, bethreequarter inch in diameter, and adjacent rods can, for example, belocated on 2 inch centers; the surface speed of the drum can be, forexample, from about to about 60 feet per minute; concentric rows of rods60 can be employed, as shown in FIG. 7; in lieu of the rods 60, thedormant material can be moved and the falling curtains formed by acylindrical plate member 62 (FIG. 6), on the order of about one-fourthinch in thickness, having closely spaced staggered ranks and rows ofcylindrical holes 64 through which the material falls for sprayapplication; the agglomerating agent may be injected directly into thenormally dormant region, as by the feed tube 56 and injection tubes 66shown in FIG. 8, so that the mixing of agglomerating agent andparticulate material takes place by way of panning action; in thepanning action operation of the unit of FIG. 8 adjacent rods 60 may belocated on 8 inch centers; and dust can be sprayed on sticky particulatematter to form, for example, prills.

As an exampleof results obtained from use of the herein describedapparatus, ground pepper dust of about 200 mesh was converted intoagglomerates of about 60 mesh by placing about 55 gallons of the dustinto the aforedescribed apparatus and then revolving drum 116 at about15 rpm. for a few minutes and spraying water from nozzles 58 intofalling curtains of the pepper.

Optionally, the embodiment of the apparatus of this invention shown inFIGS. 11 and 2 or the embodiment of the apparatus of this inventionshown in FIGS. 3-5 can be modified to additionally comprise a spiralconveyor vane disposed within the drum l6 radially inwardly of thecylindrical bundle of parallel spaced cylindrical rods 60 and preferablyadjacent thereto. This optional spiral conveyor vane helps move material36 through the drum, although it is not necessary to so move material36.

What I claim is:

l. Apparatus comprising a drum having an inlet and an outlet, conveyormeans disposed within the drum and responsive to rotative movement tomove particulate material through the drum from adjacent said inlettoward said outlet, means for imparting rotative movement to saidconveyor means, and means disposed within the drum radially inwardly ofthe radially inner margin of said conveyor means and adapted to berotated when said conveyor means is rotated to move through a radiallyintermediate region of said particulate material and thereby move andtend to lift material within said region, and cause said particulatematerial to cascade downwardly onto said particulate material in theform of one or more curtains.

2. The apparatus of claim 11, said last-mentioned means having definedtherein a plurality of spaced passageways and means operable todischarge a spray of particle-coating medium into the path of movementof particulate material in said curtains.

3. The apparatus of claim 2, said drum being cylindrical, said conveyormeans being a spiral vane attached to the inside surface of said drumand having a relatively abbreviated radial dimension, said means forimparting rotative movement to said conveyor means comprising meansmounting said drum for rotation and means for rotating said drum.

4. The apparatus of claim 3, said last-mentioned means including asubstantially cylindrical plate member supported by said drumsubstantially coaxially thereof for rotation therewith, said platemember having formed therein a plurality of closely spaced perforations.

5. A paratus comprising a cylindrical drum having an inlet and anoutlet, a spiral vane attached to the inside surface of said drum andhaving a relatively abbreviated radial dimension and responsive torotative movement to move'particulate material through the drum fromadjacent said inlet toward said outlet, means for imparting rotativemovement to said spiral vane said means comprising means mounting saiddrum for rotation and means for rotating said drum and means including aplurality of substantially parallel and substantially equispaced rodsextending substantially longitudinally of said drum and supported bysaid drum for rotation therewith and disposed within the drum radiallyinwardly of the radially inner margin of said spiral vane and adapted tobe rotated when said spiral vane is rotated to move through a radiallyintermediate region of said particulate material and thereby move andtend to lift material within said region and having defined therein aplurality of spaced passageways through which lifted particulatematerial drops downwardly, and means operable to discharge a spray ofparticle-coating medium in the path of movement of particulate materialfrom said passageways.

6. Apparatus comprising a cylindrical drum having an inlet and anoutlet, a spiral vane attached to the inside surface of said drum andhaving a relatively abbreviated radial dimension and responsive torotative movement to move particulate material through the drum fromadjacent said inlet toward said outlet, means for imparting rotativemovement to said spiral vane said means comprising means mounting saiddrum and means disposed within the drum radially inwardly of theradially inner margin of said spiral vane and adapted to be rotated whensaid spiral vane is rotated to move through a radially intermediateregion of said particulate material and thereby move and tend to liftmaterial within said region and having defined therein a plurality ofspaced passageways through which lifted particulate material dropsdownwardly, and means operable to discharge a spray of particle-coatingmedium in the path of movement of particulate material from saidpassageways, including means for returning fines from the outlet of saiddrum to the inlet end thereof, said means comprising a cylindrical shellattached to said drum outwardly and coaxially thereof to definetherewith an annular chamber, a screen for admitting fines to saidchamber from the outlet end of said drum, a spiral vane within saidchamber attached to said shell adapted to move fines through saidchamber toward the inlet end of said drum, and a plurality of portsformed in said drum adjacent the inlet end thereof and adapted to passfines from said chamber into said drum.

7. Apparatus comprising a drum having an inlet and an outlet, means forimparting rotative movement to said drum, means including a plurality ofrods extending substantially longitudinally of said drum and supportedby said drum and disposed within the drum radially inwardly of the innersurface of said drum and adapted to be rotated when said drum is rotatedto move through a radially intermediate region of said particulatematerial and thereby move and tend to lift material within said region,and having defined therein a plurality of spaced passageways throughwhich lifted particulate material cascades downwardly onto saidparticulate material in the form of one or more curtains.

8. Apparatus comprising a drum having an inlet and an outlet, means forimparting rotative movement to said drum, means disposed within the drumradially inwardly of the inner surface of said drum and adapted to berotated when said drum means is rotated to move through a radiallyintermediate region of said particulate material and thereby move andtend to lift material within said region, and cause said particulatematerial to cascade downwardly onto said particulate material in theform of one or more curtains, said last-mentioned means having definedtherein a plurality of spaced passageways and means operable todischarge a spray of particle-coating medium into the path of movementof particulate material in said curtains.

9. Apparatus comprising a drum having an inlet and an outlet, means forimparting rotative movement to said drum, means disposed within the drumradially inwardly of the inner surface of said drum and adapted to berotated when said drum means is rotated to move through a radiallyintermediate region of said particulate material and thereby move andtend to lift material within said region, and cause said particulatematerial to cascade downwardly onto said particulate material in theform of one or more curtains, said drum being cylindrical, said meansfor imparting rotative movement to said drum comprising means mountingsaid drum for rotation and means for rotating said drum.

10. Apparatus comprising a cylindrical drum having an inlet and anoutlet, means for imparting rotative movement to said drum, said meanscomprising means mounting said drum for rotation and means for rotatingsaid drum, and means including a plurality of substantially parallel andsubstantially equispaced rods extending substantially longitudinally ofsaid drum and supported by said drum for rotation therewith and disposedwithin the drum radially inwardly of the inner surface of said drum andadapted to be rotated when said drum is rotated to move through aradially intermediate region of said particulate material and therebymove and tend to lift material within said region and having definedtherein a plurality of spaced passageways through which liftedparticulate material cascades downwardly onto said particulate materialin the form of one or more curtains and means operable to discharge aspray of particle-coating medium in the path of movement of particulatematerial in said curtains.

1. Apparatus comprising a drum having an inlet and an outlet, conveyor means disposed within the drum and responsive to rotative movement to move particulate material through the drum from adjacent said inlet toward said outlet, means for imparting rotative movement to said conveyor means, and means disposed within the drum radially inwardly of the radially inner margin of said conveyor means and adapted to be rotated when said conveyor means is rotated to move through a radially intermediate region of said particulate material and thereby move and tend to lift material within said region, and cause said particulate material to cascade downwardly onto said particulate material in the form of one or more curtains.
 2. The apparatus of claim 1, said last-mentioned means having defined therein a plurality of spaced passageways and means operable to discharge a spray of particle-coating medium into the path of movement of particulate material in said curtains.
 3. The apparatus of claim 2, said drum being cylindrical, said conveyor means being a spiral vane attached to the inside surface of said drum and having a relatively abbreviated radial dimension, said means for imparting rotative movement to said conveyor means comprising means mounting said drum for rotation and means for rotating said drum.
 4. The apparatus of claim 3, said last-mentioned means including a substantially cylindrical plate member supported by said drum substantially coaxially thereof for rotation therewith, said plate member having formed therein a plurality of closely spaced perforations.
 5. Apparatus comprising a cylindrical drum having an inlet and an outlet, a spiral vane attached to the inside surface of said drum and having a relatively abbreviated radial dimension and responsive to rotative movement to move particulate material through the drum from adjacent said inlet toward said outlet, means for imparting rotative movement to said spiral vane said means comprising means mounting said drum for rotation and means for rotating said drum and means including a plurality of substantially parallel and substantially equispaced rods extending substantially longitudinally of said drum and supported by said drum for rotation therewith and disposed within the drum radially inwardly of the radially inner margin of said spiral vane and adapted to be rotated when said spiral vane is rotated to move through a radially intermediate region of said particulate material and thereby move and tend to lift material within said region and having defined therein a plurality of spaced passageways through which lifted particulate material drops downwardly, and means operable to discharge a spray of particle-coating medium in the path of movement of particulate material from said passageways.
 6. Apparatus comprising a cylindrical drum having an inlet and an outlet, a spiral vane attached to the inside surface of said drum and having a relatively abbreviated radial dimension and responsive to rotative movement to move particulate material through the drum from adjacent said inlet toward said outlet, means for imparting rotative movement to said spiral vane said means comprising means mounting said drum and means disposed within the drum radially inwardly of the radially inner margin of said spiral vane and adapted to be rotated when said spiral vane is rotated to move through a radially intermediate region of said particulate material and thereby move and tend to lift material within said region and having defined therein a plurality of spaced passageways through which lifted particulate material drops downwardly, and means operable to discharge a spray of particle-coating medium in the path of movement of particulate material from said passageways, including means for returning fines from the outlet of said drum to the inlet end thereof, said means comprising a cylindrical shell attached to said drum outwardly and coaxially thereof to define therewith an annular chamber, a screen for admitting fines to said chamber from the outlet end of said drum, a spiral vane within said chamber attached to said shell adapted to move fines through said chamber toward the inlet end of said drum, and a plurality of ports formed in said drum adjacent the inlet end thereof and adapted to pass fines from said chamber into said drum.
 7. Apparatus comprising a drum having an inlet and an outlet, means for imparting rotative movement to said drum, means including a plurality of rods extending substantially longitudinally of said drum and supported by said drum and disposed within the drum radially inwardly of the inner surface of said drum and adapted to be rotated when said drum is rotated to move through a radially intermediate region of said particulate material and thereby move and tend to lift material within said region, and having defined therein a plurality of spaced passageways through which lifted particulate material cascades downwardly onto said particulate material in the form of one or more curtains.
 8. Apparatus comprising a drum having an inlet and an outlet, means for imparting rotative movement to said drum, means disposed within the drum radially inwardly of the inner surface of said drum and adapted to be rotated when said drum means is rotated to move through a radially intermediate region of said particulate material and thereby move and tend to lift material within said region, and cause said particulate material to cascade downwardly onto said particulate material in the form of one or more curtains, said last-mentioned means having defined therein a plurality of spaced passageways and means operable to discharge a spray of particle-coating medium into the path of movement of particulate material in said curtains.
 9. Apparatus comprising a drum having an inlet and an outlet, means for imparting rotative movement to said drum, means disposed within the drum radially inwardly of the inner surface of said drum and adapted to be rotated when said drum means is rotated to move through a radially intermediate region of said particulate material and thereby move and tend to lift material within said region, and cause said particulate material to cascade downwardly onto said particulate material in the form of one or more curtains, said drum being cylindrical, said means for imparting rotative movement to said drum comprising means mounting said drum for rotation and means for rotating said drum.
 10. Apparatus comprising a cylindrical drum having an inlet and an outlet, means for imparting rotative movement to said drum, said means comprising means mounting said drum for rotation and means for rotating said drum, and means including a plurality of substantially parallel and substantially equispaced rods extending substantially longitudinally of said drum and supported by said drum for rotation therewith and disposed within the drum radially inwardly of the inner surface of said drum and adapted to be rotated when said drum is rotated to move through a radially intermediate region of said particulate material and thereby move and tend to lift material within said region and having defined thErein a plurality of spaced passageways through which lifted particulate material cascades downwardly onto said particulate material in the form of one or more curtains and means operable to discharge a spray of particle-coating medium in the path of movement of particulate material in said curtains. 